JPS6224857B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device for an automatic focusing device in an optical information recording/reproducing device, and its purpose is to clean information such as video and audio onto a recording disk in a spiral or concentric pattern by optical means. In an optical information recording and reproducing device capable of recording and reproducing information, it is possible to prevent the elastic member that supports the focusing lens of the automatic focusing device from deteriorating over time, and also to prevent dust from adhering to the focusing lens. It is an object of the present invention to provide a cleaning device for an automatic focus device in an optical information recording/reproducing device, which can remove dust or the like even if it is attached.

Optically rewritable recording materials include those that use thermal reversibility, such as plastic thermistors, and those that use phase transition, such as amorphous semiconductors. Information can be recorded, reproduced, and erased on these materials by controlling the intensity of light energy applied to them. The energy absorbed by the recording material also depends on the transport speed of the recording material (speed across the irradiation light). That is, the energy absorbed by a point on the recording material is related to the intensity of the illuminating light, the speed at which the point passes under the illuminating light, and the speed at which the point dissipates the absorbed energy. Therefore, if dust, etc. adheres to the focusing lens of the automatic focusing device that focuses the light beam onto the recording disk, not only will the transmittance of the focusing lens decrease, but a good aperture condition will not be obtained, and the recording This causes problems such as unevenness, decreased focus accuracy, and noise during playback, which adversely affects S/N.

In view of the above points, the present invention provides a cleaning device that removes dust and other deposits from the focusing lens of an automatic focusing device and prevents dust and the like from adhering to the focusing lens.
It is possible to always obtain a good aperture condition and to prevent the elastic member supporting the focusing lens from deteriorating over time. An embodiment thereof will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of the overall configuration of an optical information recording/reproducing device, where 1 is a light source such as a laser, a light beam a emitted from the light source 1 is modulated by an optical modulator 2, and a light beam b is emitted from the light source 1. occurs. The light beam b passes through the hole 4 of the flat plate 3, and the projection lens 5 reduces the light beam diameter to 1μ by the focusing lens 7 of the automatic focusing device 6.
It is reduced to a size that can be narrowed down to about m. The light beam c, which has passed through the beam splitter 8 and whose optical path has been changed by the total reflection mirror 9, is sufficiently focused by the converging lens 7 and is irradiated onto the surface of the recording disk 10. The recording disk 10 is formed by depositing a photosensitive material such as a plastic thermistor or an amorphous semiconductor onto a resin base material such as vinyl chloride. The light beam d reflected on the surface of the recording disk 10 passes through the converging lens 7 again, is reflected by the total reflection mirror 9, has its optical path changed by the beam splitter 8, and is irradiated onto the photodetector 11. The light beam d irradiated onto the photodetector 11 is used for reading information, controlling the focus of the focusing lens 7, controlling tracking of the information track, etc., but a detailed explanation thereof will be omitted here. Although not shown, the recording disk 10 is placed on a transfer device capable of being transferred in the direction of arrow A, and is transferred in the direction of arrow A while rotating. Note that e is the primary light that is blocked by the flat plate 3.

Next, the automatic focusing device will be explained using FIG. 2. On the movable frame 12, a plurality of focusing lenses 7 for converging the light beam c onto the surface of the recording disk 10 are fixed, and a coil 13 is fixed on the movable frame 12.
A bobbin 14 wound with is fixed. A magnetic circuit 1 is provided inside and outside the bobbin 14 so that the current flowing through the coil 13 cuts the magnetic flux as shown by arrow B.
7 is placed. This magnetic circuit 17 is connected to the case 18
is fixed. The movable frame 12 is supported by elastic members 19 and 20 such as leaf springs, and the support springs 19 and 20 are fixed to the case 18 and the movable frame 12.

Next, automatic focus control will be explained using FIG. 4. The light beam b emitted from the light source 1 is
After passing through the beam splitter 8, the total reflection mirror 9
The optical path is changed by , and the surface of the recording disk 10 is irradiated by the focusing lens 7 . The light beam d reflected on the surface of the recording disk 10 passes through the focusing lens 7 again, has its optical path changed by the total reflection mirror 9, and is irradiated onto the photodetector 11 by the beam splitter 8. The photodetector 11 includes two light receiving elements 11a,
11b, and when the distance between the focusing lens 7 and the recording disk 10 is within the depth of focus, the light beam d reflected on the surface of the recording disk 10 is equally irradiated onto the light receiving elements 11a and 11b, respectively. It is set up so that When the distance between the focusing lens 7 and the recording disk 10 becomes outside the depth of focus due to the vertical movement of the recording disk 10, the light beam d irradiated onto the photodetector 11 changes in the direction of the arrow c, and the light beam d irradiates the photodetector 11a. , 11b differs in the amount of light received. By sending a positive or negative signal to the coil 13 according to this displacement, the current flowing through the coil 13 is controlled, and the bobbin 14 is moved up and down by the action of the magnetic field of the magnetic circuit 17, and the light beam c is The light is controlled to be focused on the surface of the recording disk 10. This displacement detection and the automatic focus device 6 form one closed circuit, so detection and control are performed continuously.
The light beam c is always focused on the surface of the recording disk 10.

Next, regarding the cleaning device, see Figures 2 and 3.
This will be explained using figures. FIG. 2 shows a state in which the autofocus device 6 is in operation, and FIG. 3 shows a state in which it is not in operation. A cleaning substance 22 made of spongy cloth or the like is fixed to the tip of the movable body 21 in the direction of the focusing lens 7 . The movable body 21 includes a transfer means 23 consisting of a solenoid.
It is moved in the directions of arrows D and E. The solenoid constituting the transfer means 23 has a normal configuration that moves in and out by turning on and off electric current. When the automatic focus device 6 is not operating,
As shown in FIG. 3, the cleaning substance 22 is located at a position where it lightly contacts the image side (lower side in the figure) end surface of the focusing lens 7, that is, the movable body 21 is located at a first position supporting the focusing lens 7. , protected from adhesion of dust, etc. from the outside. During recording and reproduction, the movable body 21 is transported in the direction of arrow E by the transport means 23, and as shown in FIG. 2, the movable body 21 is transported to a second position away from the focusing lens 7. At that time, harmful substances such as dust adhering to the focusing lens 7 are removed.
A good aperture condition can be obtained. The cleaning substance 22 is of a removable construction and can be replaced as needed. The movable body 21
When the recording/reproducing switch is released, the recording medium is returned in the direction of arrow D by the transporting means 23, and becomes the state shown in FIG. At this time, harmful substances such as dust that have adhered during recording and reproduction are removed to prevent harmful substances such as dust from adhering. Furthermore, when the automatic focusing device 6 is not operating, the movable frame 12 is supported by the movable body 21 as shown in FIG. It can be prevented.

In the above embodiment, a case has been described in which the movable body 21 is provided on the image side (lower side in the figure) of the focusing lens 7, but it may also be provided on the incident side (upper side in the figure). Needless to say, it is more effective if it is provided on both the image side and the incident side.

As described above, according to the present invention, a cleaning substance that contacts the image side and/or incident side end surface of the focusing lens and a movable body that supports the cleaning substance are provided, and the recording and reproducing operations Since the movable body is moved in conjunction with the means for separating the cleaning substance from the end face of the focusing lens, it is possible to prevent the elastic member supporting the focusing lens from deteriorating over time, and to prevent the focusing lens of the automatic focusing device from changing over time. It is possible to remove adhering substances such as dust and the like and prevent the adhesion of dust and the like. Therefore, the transmittance of the focusing lens does not decrease, and a good aperture condition can always be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is an explanatory diagram of its overall configuration, FIGS. 2 and 3 are explanatory diagrams of its main parts, and FIG. 4 is an explanatory diagram of automatic focus control. 6... Automatic focus device, 7... Focusing lens, 10
. . . Recording disk, 21 . . . Movable body, 22 . . . Cleaning substance.

Claims (1)

[Claims] 1. An optical information recording and reproducing device capable of recording and reproducing information such as video or audio in a spiral or circular manner on a recording disk by optical means, which uses a light beam emitted from a light source onto the recording disk. an automatic focusing device comprising a focusing lens for focusing, and an elastic member movably supporting the focusing lens;
a movable body supporting an image-side or incident-side end surface of the focusing lens and having a cleaning substance in contact with the lens surface of the focusing lens, and a first position of the movable body supporting the focusing lens; and a moving means for moving the focusing lens to a second position spaced apart from the focusing lens.